docs: def interrupt_kernel_hack(signal_to_send=None):
      """
      Sends the interrupt signal to the remote kernel.  This side steps the
      (non-functional) ipython interrupt mechanisms.
      Only works on posix.
      """
      global pid
      import signal
      import os
      if pid is None:
          # Avoid errors if we couldn't get pid originally,
          # by trying to obtain it now
          pid = set_pid()
  
          if pid is None:
              echo("cannot get kernel PID, Ctrl-C will not be supported")
              return
      if not signal_to_send:
          signal_to_send = signal.SIGINT
  
      echo("KeyboardInterrupt (sent to ipython: pid " +
          "%i with signal %s)" % (pid, signal_to_send),"Operator")
      try:
          os.kill(pid, int(signal_to_send))
      except OSError:
          echo("unable to kill pid %d" % pid)
          pid = None